Building a highly functional Li1.3Al0.3Ti1.7(PO4)3/poly (vinylidene fluoride) composite electrolyte for all-solid-state lithium batteries

Highlights: • A LATP-reinforced PVDF-based solid-state composite electrolyte was prepared. • The existence of LATP permits the utilization of high Li-salt content. • A long-term electrochemical stability of the Li symmetric cell was achieved. • LiFePO₄ CPE Li battery delivers excellent cycle stability at room temperature. -- Abstract: Solid-state electrolytes have become a promising approach for rechargeable lithium batteries with enhanced safety and high energy density. However, the rigid nature of ceramic electrolytes would result in the poor interfacial contact, and polymer electrolytes suffer from inferior electrochemical performance and unsatisfied mechanical strength to suppress Li dendrites. In this work, we report a flexible Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP)-reinforced polyvinylidene fluoride (PVDF)-based solid composite electrolyte with superior performances in terms of high ionic conductivity (1.64 × 10⁻³ S cm⁻¹ at room temperature), high lithium transference number (0.45), wide electrochemical window (0–4.76 V) and enhanced tensile strength (14.2 MPa). The existence of LATP permits the utilization of high Li-salt content which increases the charge carrier concentration. Meanwhile, LATP facilitates the Li⁺ conduction process and enhances the mechanical strength, leading to a long-term electrochemical stability of symmetric Li cell for 600 h at 0.2 mA cm⁻². Assembled with LiFePO₄ cathode, the all-solid-state Li battery delivers a high capacity of 153.7 mAhg⁻¹ at 0.3 C with remarkable cycle stability. This work provides a bright future for composite polymer electrolytes in the application of all-solid-state lithium batteries.